London Fire Brigade (LFB) believes the blaze on Kingsway, Holborn, that broke out last week was caused by an electrical fault in the Victorian-era tunnels running under the road - putting paid to suggestions it may have been connected to the jewel heist in Hatton Gardens some days later.

Holborn is still getting back to normal after an electrical fire broke out last week (April 1), which took several firefighters nearly a day to get fully under control.

Thousands of people were evacuated from businesses and local residences, power was switched off for the whole area and some of the roads around the central Kingsway spot have been closed off for days, with restrictions still in place on Thursday (April 9).

Investigators now believed it was caused after a fault caused an eight-inch gas main to rupture. "There was no sign of deliberate firesetting," the LFB said.

The Metropolitan Police told City A.M. there is “nothing to suggest the two were connected”, dismissing claims to the contrary.

Ex-Flying Squad boss John O'Connor told LBC today that he believed the two major incidents - which were several days apart - could be related.

“Yeah, I think that probably was deliberate. I've never heard of an outage of electricity like that causing a fire that lasted as long as that. That seems to me too much of a coincidence," said O'Connor.

The fire on Kingsway, Holborn, broke out in the middle of last week (Source: Getty)

Police are still investigating the jewel robbery at Hatton Garden Safety Deposit, which took place over the Easter weekend. The Flying Squad was called in on Tuesday of this week and police believe 60-70 deposit boxes were opened during the burglary.

O'Connor said he believed the heist was carried out by insiders, estimating that between five and eight people would have been involved.

"There was a lot of work that went into that,” he told the radio station. “There was a lot of material to be moved. There was a lot of hard work. You need people who are fit."